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Re: [ARSCLIST] Cleaning of grooved discs
Garry Kling wrote:
Dear Margarida,
At the University of Wisconsin - Madison Mills Music Library, where I
used to work, we used a weak solution of tergitol 15-S-7 and 15-S-9.
These are mild surfactants, one of them releases water-soluble matter,
the other gets the greasy stuff. We used a mix of 1ml to 500ml of
distilled water of both (0.5ml of each, total 1:500 ratio). We also
used a Keith Monks machine. I would recommend two rinses/vacuums.
The fluid was excellent on 78's, LPs, and stable acetate
transcriptions. It was especially good at removing the vinegar
syndrome dust that is so common with transcriptions.
What in the world are you talking about??? What you are calling
"acetate transcriptions" are NOT ACETATE, they are NITRATE. Vinegar
syndrome is specific to cellulose acetate, which was used in motion
picture film and recording tape. Since these discs are not made of
cellulose acetate, what you are seeing on them has nothing to do with
vinegar syndrome but has everything to do with the leeching of the
plasticizers used to make cellulose nitrate.
It makes no more sense to call it "vinegar syndrome dust" than to call
it "pixie dust." And these discs should not be called "acetates", if
only to keep people from thinking a lacquer disc can develop vinegar
syndrome.
Let me expand on what I tried to explain a few days ago. Prior to the
introduction of cellulose nitrate lacquer coated recording discs in
1934, there were two types of solid (non-laminated) plastic PRESSINGS
made of cellulose acetate. One was the transparent discs made by Flexo,
and around 1933 this material was used by Brunswick for 16-inch
pressings. The other was a flexible opaque disc with a slightly greasy
feel that was used by World Broadcasting System. These were
clay-colored and were supplied by World with a special filing case that
had a spring-loaded pressure plate in order to keep them flat when
stored. Around 1935 World started to offer stations an option to get
the discs on a thicker and stiffer vinyl pressing that did not need the
pressure plate in the file drawers. But broadcasters had already gotten
into the habit of calling any plastic discs "acetate." I have never
smelled any vinegar on the Flexo or red World discs, but have smelled
vinegar on a special commemorative Western Electric pressing made around
1933 for Arthur C. Keller of one of his twin-groove Phila Orch stereo
masters, and on a set of 16-inch ETs pressed by World's manufacturer on
an opaque blue material also around 1933. Now these discs ARE acetate,
and can be considered at risk for vinegar syndrome, but are totally
unlike the lacquer coated recording discs you are familiar with. There
was no dust, no deterioration, only the vinegar smell. Remember, these
are pressings, not recording discs.
The transcriptions, of course, need to be handled very delicately in
the cleaning machine, or cleaned by hand.
We did not have any shellac transcriptions in our collection, so I
can't speak to it's efficacy there, but I would test on a blank side
if one is available by hand with a cotton swab to see if it would
remove any of the shellac. I would be wary. Garry Kling
You did say you had 78s there. Weren't these usually shellac? What
wouldn't harm a shellac 78 wouldn't harm a shellac transcription.
16-inch ETs and motion picture soundtrack discs were pressed of shellac
from the 1920s into the mid-30s. And cleaner reaction isn't like
removing any of the shellac like a shellac coating on furniture, it
usually results in the affected material turning white on contact of the
alcohol.
Mike Biel mbiel@xxxxxxxxx